Ubiquity and diversity of dissimilatory (per)chlorate-reducing bacteria

Journal Article · Wed Dec 01 04:00:00 EST 1999 · Applied and Environmental Microbiology

OSTI ID:20006176

Coates, J D; Michaelidou, U; Bruce, R A; O'Connor, S M; Crespi, J N; Achenbach, L A

Environmental contamination with compounds containing oxyanions of chlorine, such as perchlorate or chlorate [(per)chlorate] or chlorine dioxide, has been a constantly growing problem over the last 100 years. Although the fact that microbes reduce these compounds has been recognized for more than 50 years, only six organisms which can obtain energy for growth by this metabolic process have been described. As part of a study to investigate the diversity and ubiquity of microorganisms involved in the microbial reduction of (per) chlorate, the authors enumerated the (per) chlorate-reducing bacteria (ClRB) in very diverse environments, including pristine and hydrocarbon-contaminated soils, aquatic sediments, paper mill waste sludges, and farm animal waste lagoons. In all of the environments tested, the acetate-oxidizing ClRB represented a significant population, whose size ranged from 2.31 x 10{sup 3} to 2.4 x 10{sup 6} cells per g of sample. In addition, the authors isolated 13 ClRB from these environments. All of these organisms could grow anaerobically by coupling complete oxidation of acetate to reduction of (per) chlorate. Chloride was the sole end product of this reductive metabolism. All of the isolates could also use oxygen as a sole electron acceptor, and most, but not all, could use nitrate. The alternative electron donors included simple volatile fatty acids, such as propionate, butyrate, or valerate, as well as simple organic acids, such as lactate or pyruvate. Oxidized-minus-reduced difference spectra of washed whole-cell suspensions of the isolates had absorbance maxima close to 425, 525, and 550 nm, which are characteristic of type c cytochromes. In addition, washed cell suspensions of all of the ClRB isolates could dismutate chlorite, an intermediate in the reductive metabolism of (per) chlorate, into chloride and molecular oxygen.

• Research Organization: Southern Illinois Univ., Carbondale, IL (US)
• Sponsoring Organization: US Department of Energy
• DOE Contract Number: FG02-98ER62689
• OSTI ID: 20006176
• Journal Information: Applied and Environmental Microbiology, Journal Name: Applied and Environmental Microbiology Journal Issue: 12 Vol. 65; ISSN AEMIDF; ISSN 0099-2240
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
BACTERIA
BIODEGRADATION
CHLORATES
CHLORINE OXIDES
GROUND WATER
PERCHLORATES
REMEDIAL ACTION
SOILS